Although many people see the commercial production of ethanol as a new process, at least two of these companies -- Borregaard in Norway and SEKAB in Sweden -- have been making ethanol from wood for 60 to 100 years, respectively. In almost every sense of the word, SEKAB has been functioning as a biorefinery for more than a century.
What inspired this ingenious process? Paper. Spurred by the growing demand for high quality paper, the process of using sulfite to produce cellulose fibers was invented in a Philadelphia mill in 1866. By 1874, the process was up running in Sweden, where chemists began to tinker with the spent liquor containing sugars from the hemicellulose fraction of wood. The first sulfite ethanol plant opened in Skutskär in 1909.
The process spread, with plants more than 50 plants operating in Sweden, Finland, Norway, Russia, Austria, Switzerland over the last 80 years. Producing local fuel proved invaluable during war-time fuel shortages, and the majority of plants operated from the 1940s to the 1960s -- a period when other biomass to fuel options also flourished.
Wood ethanol was not an economically economically viable process on its own. The companies that have survived have leveraged higher value markets for the co-products they make, and this is where they differ from the new drive for cellulosic ethanol production. For example, Norway’s Borregaard only uses the hemicellulose -- about a third of the biomass -- for ethanol. The high quality cellulose fiber that once went to low-value paper is now turned into textiles or used as a specialty chemical. The sulfated lignin that was once burned to run the mill is used to make vanillin and additives for construction. Even the yeast and carbon dioxide made during in ethanol fermentation are sold.
The same economy of biomass is being explored in the new wave of cellulosic biorefineries. According to UC Berkeley Philomathia Professor and EBI Director Chris Somerville, “Many products come from a barrel of oil. Replacing the whole barrel is a challenge, but cellulosic biomass has the potential to do just that.”